For protecting a vehicle occupant laterally against a hard impact, vehicle seats in the seat back of which an airbag module is integrated are known from the state of the art. Said airbag modules are arranged either on an inside facing the occupant or on an outside facing away from the occupant of the largely rigid seat back frame in the area of a seat back frame side, wherein in this area the seat back frame extends substantially in the sitting direction (of the occupant), as visible in FIG. 1.
In an airbag module mounted to the frame inside there is a lower risk of pinching the airbag by the penetrating vehicle side structure, i.e. the airbag has more time to deploy between the occupant and the vehicle side structure. However, with such arrangement it has to be taken into consideration that the deploying airbag is not directed too strongly toward the occupant and, above all, does not excessively load the occupant during deployment even when his sitting position is shifted sideward. If, on the other hand, the airbag module is mounted to the outside of the frame, the airbag deploys away from the occupant and initially has a quite large distance from the vehicle occupant. This results in a rather late contact with the occupant. Depending on the distance between the mounted airbag module and the intruding vehicle side structure, the period of time for unhindered deployment of the airbag is very short.
EP 1 581 413 B1 shows a vehicle seat having a generic seat back, the airbag module being attached to an inside, i.e. a side of the seat back frame facing the vehicle occupant in the area of the seat back frame side. The seat back frame extends in the area of the seat back frame side in the sitting direction and is formed by a double T-beam having a high web and narrow flanges. Adjacent to the inflator, the airbag is folded at first in a multiple concertina-like manner and then in spiral shape.
It is the object of the invention to provide a seat back with an integrated airbag module, wherein even in non-ideal sitting positions of the vehicle occupant the airbag shows a deployment behavior that affects the occupant convenience as little as possible.